This invention relates generally to the combustion of solid fuels and, more particularly, to the generation and storage of sorbent used to capture mercury (Hg) in flue gas generated during coal combustion.
Volatile metals such as mercury are among the air pollutants produced by coal combustion processes. As mercury volatizes during coal combustion, it enters the flue gas generated by the combustion. If not captured, the mercury may pass into the atmosphere with the stack gases from the combustor. At least some known methods of reducing mercury emissions include the injection of an activated carbon as a sorbent that captures mercury in the flue gas. The mercury can then be removed from the flue gas and sequestered in an environmentally acceptable manner. The efficiency of mercury removal by activated carbon injection depends on coal type and the specific configuration of the emission control system, such as injection of the sorbent upstream of a particulate collector or a compact baghouse added downstream an existing electrostatic particulate control device. However, material costs of activated carbon in some cases limit the usefulness of activated carbon mercury removal systems.